Title
Comparison of bamboo native lignin and alkaline lignin modified by phase-separation method
Authors
HAO REN XIN DAI HUAMIN ZHAI ZHULAN LIU and SHIGETOSHI OMORI

Received December 2, 2013
Published Volume 49 Issue 5-6 May-June
Keywords lignin, phase separation system, characterization, aggregation, Atomic Force Microscopy, Dynamic Light Scattering Spectrometer

Abstract
In this study, native lignins were separated from bamboo using a phase separation system. Three kinds of alkaline lignins were isolated from cooking black liquor; also three kinds of alkaline lignins were modified using the phase separation system. The characteristics of bamboo native lignin and alkaline lignins were compared using Fourier Transform Infrared spectroscopy (FT-IR), Gel Permeation Chromatography (GPC), Ultraviolet Spectrometry (UV), Atomic Force Microscopy (AFM) and Dynamic Light Scattering (DLS). The solubility of lignophenols derived from bamboo and from alkaline lignins is better than that of alkaline lignins. All materials were soluble in common organic solvents and showed similar groups in FTIR spectra. GPC data indicated that the molecular weight of bamboo lignophenols (circa 4000) was larger than that of alkaline lignophenols (circa 2000). AFM images taken from the same smooth plane showed that the molecular heights of bamboo lignophenols were higher than those of alkaline lignophenols, and the aggregation of bamboo lignophenols appeared to be very uniform. DLS results indicated that the average dimension of lignophenol molecular and its aggregates ranged from 115 nm to 1560 nm, depending on the pH of the solution and the type of material examined.